Mode-Directed Tabling and Applications in the YapTab System

Tabling is an implementation technique that solves some limitations of Prolog\u27s operational semantics in dealing with recursion and redundant sub-computations. Tabling works by memorizing generated answers and then by reusing them on similar calls that appear during the resolution process. In a traditional tabling system, all the arguments of a tabled subgoal call are considered when storing answers into the table space. Traditional tabling systems are thus very good for problems that require finding all answers. Mode-directed tabling is an extension to the tabling technique that supports the definition of selective criteria for specifying how answers are inserted into the table space. Implementations of mode-directed tabling are already available in systems like ALS-Prolog, B-Prolog and XSB. In this paper, we propose a more general approach to the declaration and use of mode-directed tabling, implemented on top of the YapTab tabling system, and we show applications of our approach to problems involving Justification, Preferences and Answer Subsumption

Call subsumption mechanisms for tabled logic programs

Estágio realizado na ... e orientado pelo Eng.ºDocumento confidencial. Não pode ser disponibilizado para consultaTese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201

On applying Or-Parallelism and Tabling to logic programs

Dissertação de Doutoramento em Ciência de Computadores apresentada à Faculdade de Ciências da Universidade do Port

Tabling as a Library with Delimited Control

Tabling is probably the most widely studied extension of Prolog. But despite its importance and practicality, tabling is not implemented by most Prolog systems. Existing approaches require substantial changes to the Prolog engine, which is an investment out of reach of most systems. To enable more widespread adoption, we present a new implementation of tabling in under 600 lines of Prolog code. Our lightweight approach relies on delimited control and provides reasonable performance.Comment: 15 pages. To appear in Theory and Practice of Logic Programming (TPLP), Proceedings of ICLP 201

A workbench to develop ILP systems

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201